SARS-CoV-2 infection induces protective immunity and limits transmission in Syrian hamsters.

A critical question in understanding the immunity to SARS-COV-2 is whether recovered patients are protected against re-challenge and transmission upon second exposure. We developed a Syrian hamster model in which intranasal inoculation of just 100 TCID virus caused viral pneumonia. Aged hamsters developed more severe disease and even succumbed to SARS-CoV-2 infection, representing the first lethal model using genetically unmodified laboratory animals.